n = int(input())
d, a = map(int, input().split())


def dfs(s, g, used):
    used[s] = True
    for i in range(s + 1, n + 1):
        if g[s][i] and not (used[i]):
            dfs(i, g, used)


g = [['0'] * (n + 1) for i in range(n + 1)]
for i in range(n):
    s = input()
    for j in range(n):
        if s[j] == '1':
            g[i + 1][j + 1] = 1
k = []
i = 1
while i < n + 1:
    l1 = []
    used = [False] * (n + 1)
    dfs(i, g, used)
    for j in range(i, n + 1):
        if used[j]:
            l1.append(j)
    k.append(l1)
    for j in range(i + 1, n + 1):
        if not (used[j]):
            i = j
            break
    else:
        break
k1 = []
for i in k:
    p = []
    for j in i:
        for z in range(j + 1, i[-1] + 1):
            if g[j][z] == 1:
                p.append([j, z])
    k1.append(p)
k1.sort()
ans = (len(k1) - 1) * a
g1 = [[0] * (n + 1) for i in range(n + 1)]
for i in k1:
    p = []
    for j in i:
        if j[1] not in p:
            p.append(j[1])
        else:
            g1[j[0]][j[1]] = 'd'
            g1[j[1]][j[0]] = 'd'
    ans += (len(i) - len(p)) * d
print(ans)
for i in range(len(k1) - 1):
    g1[k1[i][-1][1]][k1[i+1][0][0]] = 'a'
    g1[k1[i+1][0][0]][k1[i][-1][1]] = 'a'
for i in g1:
    for j in i:
        print(j, end='')
    print()

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